An island at the end of the navigable river

Start with geography

The river stops being navigable here

The St Lawrence connects the Atlantic to the Great Lakes, which is a route deep into the middle of a continent. But upstream of Montreal the river drops through the Lachine Rapids, and before canals and locks, ocean-going vessels could go no further.

A break in transport is where a city grows. Cargo has to be unloaded, portaged and reloaded into smaller craft, which requires warehouses, labour, and merchants — and the people who own that transfer point capture a share of everything moving through it.

Answer the check to continue.